{"api_version":"1","generated_at":"2026-08-02T14:53:18+00:00","cve":"CVE-2026-64525","urls":{"html":"https://cve.report/CVE-2026-64525","api":"https://cve.report/api/cve/CVE-2026-64525.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64525","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64525"},"summary":{"title":"xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit\n\nThe struct pernet_operations docstring in include/net/net_namespace.h\nexplicitly warns against blocking RCU primitives in .exit handlers:\n\n    Exit methods using blocking RCU primitives, such as\n    synchronize_rcu(), should be implemented via exit_batch.\n    [...]\n    Please, avoid synchronize_rcu() at all, where it's possible.\n\n    Note that a combination of pre_exit() and exit() can\n    be used, since a synchronize_rcu() is guaranteed between\n    the calls.\n\nxfrm_policy_fini() violates this: it calls synchronize_rcu() before\nfreeing the policy_bydst hash tables (so no RCU reader is mid-\ntraversal at free time), but runs from xfrm_net_ops.exit -- once per\nnamespace -- so a cleanup_net() of N namespaces pays N full RCU\ngrace periods serially.\n\nUse the documented pre_exit/exit split. Move the policy flush (and\nthe workqueue drains it depends on) into a new .pre_exit handler;\nxfrm_policy_fini() then runs in .exit and frees the hash tables\nafter the synchronize_rcu_expedited() that cleanup_net() guarantees\nbetween the two phases. Providing O(1) RCU grace periods per batch\ninstead of O(N).\n\nObserved on Linux 6.18 with a workload doing unshare(CLONE_NEWNET)\nat ~13/sec sustained: cleanup_net() and the netns_wq rescuer kthread\nboth stuck in xfrm_policy_fini()'s synchronize_rcu(), >300k struct\nnet accumulated in the cleanup queue, Percpu in /proc/meminfo climbed\nto 130+ GB on 256-CPU hosts, and memcg OOMs followed. setup_net and\n__put_net counts were balanced, ruling out a refcount leak.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:38","updated_at":"2026-07-25 10:17:38"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/d14ae8ef88c2c6590e107db61b6adce148cec7b3","name":"https://git.kernel.org/stable/c/d14ae8ef88c2c6590e107db61b6adce148cec7b3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3e52417318473782012b236d0325bf7d2266a597","name":"https://git.kernel.org/stable/c/3e52417318473782012b236d0325bf7d2266a597","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/91cc13978ab0bc6f669139f53e7e613a860d10e0","name":"https://git.kernel.org/stable/c/91cc13978ab0bc6f669139f53e7e613a860d10e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bca6386dc08750fc7cdcbc7683473748ba3114b9","name":"https://git.kernel.org/stable/c/bca6386dc08750fc7cdcbc7683473748ba3114b9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64525","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64525","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 438b1f668ad58f46ce699bb48e4698a7839e3f9e bca6386dc08750fc7cdcbc7683473748ba3114b9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3733fce2871c9bca9dd18a1a23b1432ea215a094 91cc13978ab0bc6f669139f53e7e613a860d10e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 069daad4f2ae9c5c108131995529d5f02392c446 d14ae8ef88c2c6590e107db61b6adce148cec7b3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 069daad4f2ae9c5c108131995529d5f02392c446 3e52417318473782012b236d0325bf7d2266a597 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b66920a3348c0f63ba18365248fa21fbf0b3a937 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 33a3149dd81a1e2f52b80ee1e0fc380b39f3d028 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.83 6.12.93 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.24 6.18.35 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.136 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19.14 6.20 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64525","cve":"CVE-2026-64525","epss":"0.001560000","percentile":"0.052520000","score_date":"2026-07-29","updated_at":"2026-07-30 00:09:16"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/xfrm/xfrm_policy.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"bca6386dc08750fc7cdcbc7683473748ba3114b9","status":"affected","version":"438b1f668ad58f46ce699bb48e4698a7839e3f9e","versionType":"git"},{"lessThan":"91cc13978ab0bc6f669139f53e7e613a860d10e0","status":"affected","version":"3733fce2871c9bca9dd18a1a23b1432ea215a094","versionType":"git"},{"lessThan":"d14ae8ef88c2c6590e107db61b6adce148cec7b3","status":"affected","version":"069daad4f2ae9c5c108131995529d5f02392c446","versionType":"git"},{"lessThan":"3e52417318473782012b236d0325bf7d2266a597","status":"affected","version":"069daad4f2ae9c5c108131995529d5f02392c446","versionType":"git"},{"status":"affected","version":"b66920a3348c0f63ba18365248fa21fbf0b3a937","versionType":"git"},{"status":"affected","version":"33a3149dd81a1e2f52b80ee1e0fc380b39f3d028","versionType":"git"},{"lessThan":"6.12.93","status":"affected","version":"6.12.83","versionType":"semver"},{"lessThan":"6.18.35","status":"affected","version":"6.18.24","versionType":"semver"},{"lessThan":"6.7","status":"affected","version":"6.6.136","versionType":"semver"},{"lessThan":"6.20","status":"affected","version":"6.19.14","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/xfrm/xfrm_policy.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.0"},{"lessThan":"7.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.93","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.35","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"6.12.83","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"6.18.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"7.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"7.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.136","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.19.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit\n\nThe struct pernet_operations docstring in include/net/net_namespace.h\nexplicitly warns against blocking RCU primitives in .exit handlers:\n\n    Exit methods using blocking RCU primitives, such as\n    synchronize_rcu(), should be implemented via exit_batch.\n    [...]\n    Please, avoid synchronize_rcu() at all, where it's possible.\n\n    Note that a combination of pre_exit() and exit() can\n    be used, since a synchronize_rcu() is guaranteed between\n    the calls.\n\nxfrm_policy_fini() violates this: it calls synchronize_rcu() before\nfreeing the policy_bydst hash tables (so no RCU reader is mid-\ntraversal at free time), but runs from xfrm_net_ops.exit -- once per\nnamespace -- so a cleanup_net() of N namespaces pays N full RCU\ngrace periods serially.\n\nUse the documented pre_exit/exit split. Move the policy flush (and\nthe workqueue drains it depends on) into a new .pre_exit handler;\nxfrm_policy_fini() then runs in .exit and frees the hash tables\nafter the synchronize_rcu_expedited() that cleanup_net() guarantees\nbetween the two phases. Providing O(1) RCU grace periods per batch\ninstead of O(N).\n\nObserved on Linux 6.18 with a workload doing unshare(CLONE_NEWNET)\nat ~13/sec sustained: cleanup_net() and the netns_wq rescuer kthread\nboth stuck in xfrm_policy_fini()'s synchronize_rcu(), >300k struct\nnet accumulated in the cleanup queue, Percpu in /proc/meminfo climbed\nto 130+ GB on 256-CPU hosts, and memcg OOMs followed. setup_net and\n__put_net counts were balanced, ruling out a refcount leak."}],"providerMetadata":{"dateUpdated":"2026-07-25T09:20:49.256Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bca6386dc08750fc7cdcbc7683473748ba3114b9"},{"url":"https://git.kernel.org/stable/c/91cc13978ab0bc6f669139f53e7e613a860d10e0"},{"url":"https://git.kernel.org/stable/c/d14ae8ef88c2c6590e107db61b6adce148cec7b3"},{"url":"https://git.kernel.org/stable/c/3e52417318473782012b236d0325bf7d2266a597"}],"title":"xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64525","datePublished":"2026-07-25T09:20:49.256Z","dateReserved":"2026-07-19T15:36:31.794Z","dateUpdated":"2026-07-25T09:20:49.256Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:38","lastModifiedDate":"2026-07-25 10:17:38","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64525","Ordinal":"1","Title":"xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_ex","CVE":"CVE-2026-64525","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64525","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit\n\nThe struct pernet_operations docstring in include/net/net_namespace.h\nexplicitly warns against blocking RCU primitives in .exit handlers:\n\n    Exit methods using blocking RCU primitives, such as\n    synchronize_rcu(), should be implemented via exit_batch.\n    [...]\n    Please, avoid synchronize_rcu() at all, where it's possible.\n\n    Note that a combination of pre_exit() and exit() can\n    be used, since a synchronize_rcu() is guaranteed between\n    the calls.\n\nxfrm_policy_fini() violates this: it calls synchronize_rcu() before\nfreeing the policy_bydst hash tables (so no RCU reader is mid-\ntraversal at free time), but runs from xfrm_net_ops.exit -- once per\nnamespace -- so a cleanup_net() of N namespaces pays N full RCU\ngrace periods serially.\n\nUse the documented pre_exit/exit split. Move the policy flush (and\nthe workqueue drains it depends on) into a new .pre_exit handler;\nxfrm_policy_fini() then runs in .exit and frees the hash tables\nafter the synchronize_rcu_expedited() that cleanup_net() guarantees\nbetween the two phases. Providing O(1) RCU grace periods per batch\ninstead of O(N).\n\nObserved on Linux 6.18 with a workload doing unshare(CLONE_NEWNET)\nat ~13/sec sustained: cleanup_net() and the netns_wq rescuer kthread\nboth stuck in xfrm_policy_fini()'s synchronize_rcu(), >300k struct\nnet accumulated in the cleanup queue, Percpu in /proc/meminfo climbed\nto 130+ GB on 256-CPU hosts, and memcg OOMs followed. setup_net and\n__put_net counts were balanced, ruling out a refcount leak.","Type":"Description","Title":"xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_ex"}]}}}